Generators - Gas, Diesel or Propane, Best makes models?

If you intend to run the A/C I recommend sticking with gas
A dual fuel conversion can be handy for quick eng use and easy storage, no gas to gum up carb
But not so much fun changing propane cylinders every day when powering the A/C
And get one at least 3000 watts 2000 is very IFFY for powering a/c
It depends entirely on a small easy start a/c with low power needs and not already 100° outside